We report a simple and effective method to realize desirable interfacial property for inverted planar per-ovskite solar cells(PSCs)by using small molecule ethanediamine for the construction of a novel polyelec-trolyte hole transport material(P3CT-ED HTM).It is found that P3CT-ED can not only improve the hole transport property of P3CT-K but also improve the crystallinity of adjacent perovskite film.In addition,the introduction of ethanediamine into P3CT realigns the conduction and valence bands upwards,passi-vates surface defects and reduces nonradiative recombination.As a consequence,compared to P3CT-K hole transport layer(HTL)based devices,the average power conversion efficiency(PCE)is boosted from 17.2％to 19.6％for the counterparts with P3CT-ED,with simultaneous enhancement in open circuit volt-age and fill factor.The resultant device displays a champion PCE of 20.5％with negligible hysteresis.